错误而运行JDBC程序

问题描述：

我使用MySQL 5.5和MySQL连接器的Java-5.1.15。（两者都安装了新）错误而运行JDBC程序

我尝试了JDBC程序通过使用记事本和命令提示符。

我的JDBC程序：

import java.sql.*; 
import java.io.*; 


public class MysqlConnect{ 
    public static void main(String[] args) { 

    System.out.println("MySQL Connect Example."); 
    Connection conn = null; 
    String url = "jdbc:mysql://localhost:3306/"; 
    String dbName = "employement"; 
    String driver = "com.mysql.jdbc.Driver"; 
    String userName = "root"; 
    String password = "12345"; 
    try { 
     Class.forName(driver).newInstance(); 
     conn = DriverManager.getConnection(url+dbName,userName,password); 
     System.out.println("Connected to the database"); 
     conn.close(); 
     System.out.println("Disconnected from database"); 
    } catch (Exception e) { 
     e.printStackTrace(); 
    } 
    } 
}

我创建了一个名为到工作在MySQL数据库....

我尝试运行此程序...

C:\Users\Innodea\Desktop>javac MysqlConnect.java 

C:\Users\Innodea\Desktop>java MysqlConnect 
Exception in thread "main" java.lang.NoClassDefFoundError: MysqlConnect 
Caused by: java.lang.ClassNotFoundException: MysqlConnect 
     at java.net.URLClassLoader$1.run(URLClassLoader.java:202) 
     at java.security.AccessController.doPrivileged(Native Method) 
     at java.net.URLClassLoader.findClass(URLClassLoader.java:190) 
     at java.lang.ClassLoader.loadClass(ClassLoader.java:307) 
     at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301) 
     at java.lang.ClassLoader.loadClass(ClassLoader.java:248) 
Could not find the main class: MysqlConnect. Program will exit.

如何清除这个错误？

而且我已经试过如下，

C:\Users\Innodea\Desktop>set classpath=C:\Program Files\MySQL\mysql-connector-ja 
va-5.1.15\mysql-connector-java-5.1.15.jar 

C:\Users\Innodea\Desktop>javac MysqlConnect.java 

C:\Users\Innodea\Desktop>java MysqlConnect 
Exception in thread "main" java.lang.NoClassDefFoundError: MysqlConnect 
Caused by: java.lang.ClassNotFoundException: MysqlConnect 
     at java.net.URLClassLoader$1.run(URLClassLoader.java:202) 
     at java.security.AccessController.doPrivileged(Native Method) 
     at java.net.URLClassLoader.findClass(URLClassLoader.java:190) 
     at java.lang.ClassLoader.loadClass(ClassLoader.java:307) 
     at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301) 
     at java.lang.ClassLoader.loadClass(ClassLoader.java:248) 
Could not find the main class: MysqlConnect. Program will exit.

同样也同样发生错误，请帮我清除此错误和运行JDBC程序....

答

java -cp .;C:\Program Files\MySQL\mysql-connector-java-5.1.15\mysql-connector-java-5.1.15.jar MysqlConnect

答

使用-cp开关应该工作

 
java -cp=.;C:\Program Files\MySQL\mysql-connector-java-5.1.15\mysql-connector-java-5.1.15.jar MysqlConnect

它几乎从来不需要设置CLASSPATH环境变量

答

尝试使用此 -

java -cp %CLASSPATH%;.; MysqlConnect.java

或者补充。当前目录 - 到classpath像

set classpath=C:\Program Files\MySQL\mysql-connector-ja va-5.1.15\mysql-connector-java-5.1.15.jar;.;

您当前的类也需要在类路径中，因此点读它。

错误而运行JDBC程序

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